net: axienet: Handle jumbo frames for lesser frame sizes

In the current implementation, jumbo frames are supported only
for the frame sizes > 16K. This patch corrects this logic to
handle jumbo frames for lesser frame sizes (< 16K) ensuring jumbo frame
MTU is within the limit of max frame size configured in the h/w
design.

Signed-off-by: Srikanth Thokala <sthokal@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet.h b/drivers/net/ethernet/xilinx/xilinx_axienet.h
index 4c9b4fa1d3c1cbed1fc223634adca0a2cb7b5807..4e309440964a9344153f45c24f790336be48d051 100644 (file)
--- a/drivers/net/ethernet/xilinx/xilinx_axienet.h
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet.h
@@ -11,16 +11,16 @@
 #include <linux/netdevice.h>
 #include <linux/spinlock.h>
 #include <linux/interrupt.h>
+#include <linux/if_vlan.h>
 
 /* Packet size info */
 #define XAE_HDR_SIZE                   14 /* Size of Ethernet header */
-#define XAE_HDR_VLAN_SIZE              18 /* Size of an Ethernet hdr + VLAN */
 #define XAE_TRL_SIZE                    4 /* Size of Ethernet trailer (FCS) */
 #define XAE_MTU                              1500 /* Max MTU of an Ethernet frame */
 #define XAE_JUMBO_MTU                9000 /* Max MTU of a jumbo Eth. frame */
 
 #define XAE_MAX_FRAME_SIZE      (XAE_MTU + XAE_HDR_SIZE + XAE_TRL_SIZE)
-#define XAE_MAX_VLAN_FRAME_SIZE  (XAE_MTU + XAE_HDR_VLAN_SIZE + XAE_TRL_SIZE)
+#define XAE_MAX_VLAN_FRAME_SIZE  (XAE_MTU + VLAN_ETH_HLEN + XAE_TRL_SIZE)
 #define XAE_MAX_JUMBO_FRAME_SIZE (XAE_JUMBO_MTU + XAE_HDR_SIZE + XAE_TRL_SIZE)
 
 /* Configuration options */
@@ -407,8 +407,7 @@ struct axidma_bd {
  *               Txed/Rxed in the existing hardware. If jumbo option is
  *               supported, the maximum frame size would be 9k. Else it is
  *               1522 bytes (assuming support for basic VLAN)
- * @jumbo_support: Stores hardware configuration for jumbo support. If hardware
- *                can handle jumbo packets, this entry will be 1, else 0.
+ * @rxmem:     Stores rx memory size for jumbo frame handling.
  */
 struct axienet_local {
        struct net_device *ndev;
@@ -446,7 +445,7 @@ struct axienet_local {
        u32 rx_bd_ci;
 
        u32 max_frm_size;
-       u32 jumbo_support;
+       u32 rxmem;
 
        int csum_offload_on_tx_path;
        int csum_offload_on_rx_path;

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index b83425393a24308d3e418fe80daf01ca60c5dde8..b1081e1893b092ccc68449b9143a5721a859d805 100644 (file)
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -471,14 +471,16 @@ static void axienet_device_reset(struct net_device *ndev)
        __axienet_device_reset(lp, &ndev->dev, XAXIDMA_RX_CR_OFFSET);
 
        lp->max_frm_size = XAE_MAX_VLAN_FRAME_SIZE;
+       lp->options |= XAE_OPTION_VLAN;
        lp->options &= (~XAE_OPTION_JUMBO);
 
        if ((ndev->mtu > XAE_MTU) &&
-           (ndev->mtu <= XAE_JUMBO_MTU) &&
-           (lp->jumbo_support)) {
-               lp->max_frm_size = ndev->mtu + XAE_HDR_VLAN_SIZE +
-                                  XAE_TRL_SIZE;
-               lp->options |= XAE_OPTION_JUMBO;
+               (ndev->mtu <= XAE_JUMBO_MTU)) {
+               lp->max_frm_size = ndev->mtu + VLAN_ETH_HLEN +
+                                       XAE_TRL_SIZE;
+
+               if (lp->max_frm_size <= lp->rxmem)
+                       lp->options |= XAE_OPTION_JUMBO;
        }
 
        if (axienet_dma_bd_init(ndev)) {
@@ -1027,15 +1029,15 @@ static int axienet_change_mtu(struct net_device *ndev, int new_mtu)
 
        if (netif_running(ndev))
                return -EBUSY;
-       if (lp->jumbo_support) {
-               if ((new_mtu > XAE_JUMBO_MTU) || (new_mtu < 64))
-                       return -EINVAL;
-               ndev->mtu = new_mtu;
-       } else {
-               if ((new_mtu > XAE_MTU) || (new_mtu < 64))
-                       return -EINVAL;
-               ndev->mtu = new_mtu;
-       }
+
+       if ((new_mtu + VLAN_ETH_HLEN +
+               XAE_TRL_SIZE) > lp->rxmem)
+               return -EINVAL;
+
+       if ((new_mtu > XAE_JUMBO_MTU) || (new_mtu < 64))
+               return -EINVAL;
+
+       ndev->mtu = new_mtu;
 
        return 0;
 }
@@ -1556,16 +1558,14 @@ static int axienet_of_probe(struct platform_device *op)
                }
        }
        /* For supporting jumbo frames, the Axi Ethernet hardware must have
-        * a larger Rx/Tx Memory. Typically, the size must be more than or
-        * equal to 16384 bytes, so that we can enable jumbo option and start
-        * supporting jumbo frames. Here we check for memory allocated for
-        * Rx/Tx in the hardware from the device-tree and accordingly set
-        * flags. */
+        * a larger Rx/Tx Memory. Typically, the size must be large so that
+        * we can enable jumbo option and start supporting jumbo frames.
+        * Here we check for memory allocated for Rx/Tx in the hardware from
+        * the device-tree and accordingly set flags.
+        */
        p = (__be32 *) of_get_property(op->dev.of_node, "xlnx,rxmem", NULL);
-       if (p) {
-               if ((be32_to_cpup(p)) >= 0x4000)
-                       lp->jumbo_support = 1;
-       }
+       if (p)
+               lp->rxmem = be32_to_cpup(p);
        p = (__be32 *) of_get_property(op->dev.of_node, "xlnx,phy-type", NULL);
        if (p)
                lp->phy_type = be32_to_cpup(p);